Tetrafluorodithiosuccinyl difluoride and method of preparing same

ABSTRACT

Tetrafluorodithiosuccinyl difluoride is prepared by reacting trifluorovinyl iodide with sulfur in the vapor phase. The product is polymerized by ionic polymerization to polymers which are corrosion resistant and have nonstick surfaces.

United States Patent [191 Middleton [451 Sept. 23, 1975 I 5 TETRAFLUORODITHIOSUCCINYL DIFLUORIDE AND METHOD OF PREPARING SAME [52] U.S. Cl. 260/543 F; 116/161; 260/79 [51] Int. CI. C07C 153/00 [58] Field of Search 260/543 F [56] References Cited UNITED STATES PATENTS 2,962,529 11/1960 Marquis ..260/543F 3,069,395 12/1962 Middleton 260/543 F 3,117,977 1/1964 Middleton.... 260/543 F FOREIGN PATENTS OR APPLICATIONS 868,459 5/1961 United Kingdom 260/543 F OTHER PUBLICATIONS Middleton et al., J. Org. Chem. 30, 13-75, (1965).

Primary Examiner-John F. Terapane [57] ABSTRACT Tetrafluorodithiosuccinyl difluoride is prepared by reacting trifluorovinyl iodide with sulfur in the vapor phase. The product is polymerized by ionic polymerization to polymers which are corrosion resistant and have nonstick surfaces.

2 Claims, No Drawings .Middl eton et= .al..' te'ach:.the -reaction-- of chlorotriflu- :oroethylene with refluxings-ulfur vapors,..;

.QFfCRQl 2 the reaction of .bromotrifluoroethylene. with .refl uxin sulfur vapors, 1

and the reaction of tetrafluoroethylene with refluxing sulfur vapors.

In Jour. Polym. Sci., part A, vol. 3, pp. 4115-4129 I965), Middleton et al. teach the polymerization of thioacyl fluorides.

SUMMARY OF THE INVENTION In accordance with this invention the novel compound, tetrafluorodithiosuccinyl difluoride, has been discovered. This compound is prepared by reacting DETAILED DESCRIPTION OF THE INVENTION Tetrafluorodithiosuccinyl difluoride is prepared in accordance with the equation:

ll ll 2 CF =CFI as FCCFECFECF I2 A convenient method of carrying out this reaction is to pass hot trifluoroiodoethylene gas into a vessel in which sulfur vapors are refluxing (about 445C. at 776 mm Hg) and then passing the reaction effluent into a condenser system which will condense the liquid produc below its boiling point of about 85C. 1

Tetrafluorodithiosuccinyl difluoride is polymerize in accordance with the equation:

CCFCFC l 22 S/ This polymerization is carried out in the presence of an ionic polymerization initiator. The polymerization can be carried out by either= bulkor solution methods. at temperatures ranging frorn about downlto about '-1 C'.;' or 'lower,'-and-pressures .varying' over a wide rangel The preferred temperature i's inithe range of --.amides .zsuch :m'ethylacetamide; primary, secondary and tertiary Famines su'chv as triethylamine, diisopropylamine; N-

' about '50 to l 00C. .andthe-preferred pressure is at- -mosphei'i c.'- Undenthese preferred-conditions solid polymers'are obtained'. The polymerization times required vary from about I- hour to several days, e.g.,' about 3-4 "days, depending on the particular operating conditions and the specific initiators being used.

" Suitable solvents for the polymerization reaction include ethers such as dimethyl ether, diethyl ether, di-npropyl ether, diisopropyl ether, methylethy'l e ther, 1,2-

dimethoxyethane, 1 methyl propyl ether, 2- methoxypropane, 2-methoxybutane and tetrahydrofuran, and hydrocarbons such'as ethane, propane, butane, isobutane and pentane'." Djiethyl ether is a particularly effective' solvent.

- A wide varietyof ionic,initiators'canbe. usedinthis =process.-Speciflc-initiators that are operable include as dimethylformamide, and v N- methylmorpholine, tetrakis( dimethylamino )etl'iylene; phosphines such as triphenylphosphine; tetraalkyl and alkyl aryl ammonium chlorides having no hydrogen on the quaternary ammonium nitrogen such as tetraethylammonium chloride; cesium fluoride; and methal alkyls such as butyl lithium. Anionic initiators, particularly dimethylformamide, are especially suitable for making high molecular weight polymers. The ionic initiators are normally employed in concentrations ranging from about 0.2 to 20 percent by weight based on the monomer, but amounts as low as about 0.01 percent or even less, can be used effectively.

Poly(tetrafluorodithiosuccinyl difluoride) is resistant to acids and most common solvents, including nitric acid, gasoline, and fuel oil, and therefore can be used in the manufacture of articles that need to be resistant to these materials. For example, metal articles can be coated with a film of the polymer to provide corrosion resistance. Since poly(tetrafluorodithiosuccinyl difluoride) has a low coefficient of friction, objects can be coated with the polymer to provide non-stick surfaces or permanently lubricated surfaces.

EXAMPLES OF THE INVENTION The following examples, illustrating the preparation of tetrafluorodithiosuccinyl difluoride and poly(tetrafluorodithiosuccinyl difluoride), are given without any intention that the invention be limited thereto. All percentages are by weight and temperatures are in degrees Centigrade.

EXAMPLE I PREPARATION OF TETRAFLUORODITHIOSUCCINYL DIFLUORIDE A stream of nitrogen gas was bubbled into a flask containing g (0.72 mole) of freshly distilled trifluoroiodoethylene, and the entrained vapors were then passed through a 500-ml flask having two necks 6 inches long and containing 150 g of sulfur heated to reflux, and then through a 12-inch horizontal wide-bore air condenser into an ice-cooled trap. Iodine crystals deposited in the air condenser, and a dark liquid condensed in the trap. The rate of nitrogen flow was adjusted so that the entire sample of trifluoroiodoethylene was added in about 2 hours. The condensate in the trap was distilled to give 41.32 g (61 percent) of tetrafluorodithiosuccinyl difiuoride as a red-brovm liquid: bp 8485.5;

A 428 my. (6 46.5), 294 mu (6 171) and 220 my. (e 11,300);

F nmr (CCI F): 8+66.2 ppm (m, 2F), 109.1 ppm (m, 4F).

Anal. Calcd for C F S C, 21.24; F, 50.41; S, 28.35

Found: C, 21.34; F, 50.47; S, 28.47.

EXAMPLE 2 POLYMERIZATION OF TETRAFLUORODITHIOSUCCINYL DIFLUORIDE A solution of 4.5 g of tetrafluorodithiosuccinyl difluoride in 50 ml of ether was cooled to 78, and 1 drop of dimethylformamide was added. Cooling was continued for 2 hours, and then the reaction was warmed to room temperature. The precipitated polymer was collected on a filter, washed with ether and dried in air.

There was obtained 2.3 g. of the polymer as a light pink powder, mp 242-267 (viscous melt). No solvent was found for the polymer, but a film was pressed at (10,000 lbs/in Anal. Calcd for (C F S C, 21.24; H, 0.00; F, 50.40; S, 28.35

Found C, 21.31; H, 0.36; F, 50.15; S, 28.97

Although the invention has been described and exemplified by way of specific embodiments, it is not intended that it be limited thereto. As will be apparent to those skilled in the art, numerous modifications and variations of these embodiments can be made without departing from the spirit of the invention or the scope of the following claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Tetrafluorodithiosuccinyl difluoride.

2. The-method of preparing tetrafluorodithiosuccinyl difluoride which comprises reacting trifluoroiodoethylene with sulfur vapors at a temperature from 400 to 600C. 

1. TETRAFLUORODITHIOSUCCINYL DIFLUORIDE.
 2. THE METHOD OF PREPARING TETRAFLUORODITHIOSUCCINYL DIFLUORIDE WHICH COMPRISES REACTING TETRAFLUOROIDOETHYLENE WITH SULFUR VAPORS AT A TEMPREATURE FROM 400* TO600*C. 